Make sure the area that you will be repairing is clean and has BEEN DRY for 12 hours. Please note that you will be handling a solvent-based sealer, so you should always wear a pair of safety goggles and the protective gloves while handling the sealer. Opening a window to gain some fresh air and cross ventilation is a good idea. This sealer will take 12 hours to cure, so assume that your concrete will not be in service for one day.